Aerotech Fans
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Aerotech Fans
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Technical answers to common questions about industrial blowers.
A fluid coupling is a hydrodynamic transmission device used on massive ID fans to provide a soft start. It utilizes hydraulic fluid shear to smoothly accelerate the heavy impeller, eliminating the extreme mechanical shock and inrush current associated with Direct-On-Line (DOL) starting.
Severe vibration is typically caused by severe impeller imbalance due to localized particulate buildup, abrasive wear on the blades, or bearing failure. Continuous vibration monitoring systems are recommended to detect these imbalances before they cause catastrophic shaft failure.
For heavy-duty ID fans operating in high-temperature environments, bearings should typically be greased every 2,000 to 4,000 operating hours using high-temperature lithium complex grease, though automated continuous lubrication systems are highly recommended to prevent premature failure.
Our double-stage high-pressure blowers can generate up to 2500 mm w.g. static pressure by utilizing two impellers mounted in series on a common shaft, effectively doubling the compression capability of a single-stage unit.
If a 3-phase motor is wired incorrectly and an ID fan runs backwards, a backward-curved or radial impeller will still move air in the correct direction due to centrifugal force, but it will operate at a fraction of its design CFM and efficiency, causing severe system underperformance.
An ATEX certified centrifugal blower requires an explosion-proof motor, anti-sparking brass or aluminum rub-rings around the impeller inlet, and a fully grounded carbon steel or stainless housing to prevent static discharge in explosive gas or dust environments.
For dense phase pneumatic conveying of heavy materials like cement or fly ash, the duct velocity must be maintained between 3,500 and 4,500 Feet Per Minute (FPM). If velocity drops below this threshold, the particulate will fall out of suspension and instantly block the pipeline.
To prevent severe system effect (aerodynamic turbulence that destroys fan efficiency), there must be a minimum of 2.5 to 3 duct diameters of straight, un-obstructed ductwork immediately following the discharge of a centrifugal blower before the first elbow or transition.
Forward-curved centrifugal impellers are acoustically the quietest because they generate high volumetric airflow at very low RPMs. However, they are strictly limited to clean-air applications like HVAC, as any particulate will instantly foul the tight blade spacing.
A heavy-duty centrifugal blower must be mechanically decoupled from the rigid ductwork using flexible fire-rated canvas or neoprene connections. Without this isolation, the inherent harmonic vibration of the blower will transmit directly into the sheet metal, turning the entire duct network into a massive acoustic amplifier.
Rubber (neoprene) isolation pads are sufficient for high-RPM, low-mass fans. However, heavy-duty low-RPM blowers (like Induced Draft fans) require restrained spring isolators. Springs provide the high static deflection required to absorb low-frequency harmonic vibrations that rubber pads cannot dampen.
